Device for attachment of coil ends in generator stator high-voltage winding

ABSTRACT

A device for attachment of coil ends in a generator stator high-voltage winding includes insulation spacers (13) disposed on external surfaces of the coil end bars (16), auxiliary spacers disposed between coil end bars (16), a case (1), spring stops (15) anchored inside the case (1), and planks (14). The case (1) is made of two coaxial truncated-cone members (2 and 3) and a part of a torus member (4) made integral therewith and incorporating a joint (5) with a seal (6). Each plank (14) is arranged between two insulation spacers (13), and the insulation spacers (13) are arranged between the coil end bars (16) and the spring stops (15). The insulation spacers (13), the planks (14), the spring (15) and a side surface of the case (1) form cooling passages.

TECHNICAL FIELD

The present invention relates in general to electric machine building,and is particularly concerned with devices for attachment of coil endsin generator stator high-voltage windings.

BACKGROUND ART

The present-day technology of generator construction is characterized bytrends toward building-up the unit power of generators, with the resultthat in the present state of the art, the generator stator windings mustbe designed to handle high rated currents (from 10 to 60 kA). Hence, atthe existing levels of generator voltages (from 15 to 27 kV), thedimensions of stator winding bars must be increased substantially, andthe length of stator winding coil end bars must be extended accordingly.Furthermore, manufacture of modern high-power generators is practicaldue to the realization of direct liquid cooling of the generatorwinding, with the dimensions of the generator stator winding barsincreased still further to furnish passages for supply of coolant. Inits turn, the length of the stator winding coil end bars has extendedeven more, with direct cooling of the stator winding bars provided bymeans of intricate devices for supply of coolant which in most cases donot permit raising the generator voltage substantially above theestablished level /cf. V. V. Titov, G. M. Khutoretzkiy, G. A.Zagorodnaya, G. P. Vartanian, D. I. Zaslavskiy and A. I. Smotrov, "Turbo-Generators. Design and Construction", Energia Publishers, 1967,Leningrad, pp. 38 through 45 and 70 through 72 (in Russian)/.

Known in the art is a device for attachment of generator winding coilend bars, wherein the coil ends are held by shrink rings embracing thebars on the outside by a set of spacers disposed in gaps betweenindividual bars. Each bar in a bottom and a top layer is fastened toeach shrink ring. The shrink rings are attached to the generator statorby means of brackets. The spacers are fastened to the bars, and thecoolant is supplied to the stator winding bars through rubber hoses (cf.V. V. Titov, G. M. Khutoretzkiy, G. A. Zagorodnaya, G. P. Vartanian, D.I. Zaslavskiy and A. I. Smotrov, "Turbo-Generators. Design andConstruction", Energia Publishers, 1967, Leningrad, pp. 188 through192).

In the prior-art device, the winding coil end bars are attached to thegenerator stator on one side only, and this is obviously insufficientfor longer bars of the winding coil ends used in higher unit powergenerators designed for output voltages above the existing level, sothat the generator dependability is impaired.

The above method of attachment of the shrink rings and spacers in theprior-art generator is not quite reliable.

The closest analog to our invention is a device for attachment of coilends in a generator stator high-voltage winding (cf. USSR Inventor'sCertificate No. 215305 H02K 3/50, published in the Bulletin ofDiscoveries, Inventions, Designs and Trade Marks, No. 13, Nov. 3, 1963).The foregoing device incorporates a shrink ring mounting supportingbrackets attached thereto, insulation spacers furnished with spacerwedges disposed therebetween and positioned on external surfaces of thecoil end bars, and extra spacers furnished with the spacer wedgesdisposed therebetween and positioned between the coil end bars. Theinsulation spacers are clamped at the ends thereof by insulation rings.A hollow shrink ring through which coolant is supplied serves as acoolant header.

The prior-art method of attachment of the generator stator high-voltagewinding coil ends permits securing the coil end bars only on one sidefacing the generator end plate, and is therefore insufficientlyreliable, the coil end bars in modern high-power generators being quitelong (about 1/5 of the active length thereof per each side).

Owing to the use of supporting brackets and shrink rings for attachmentof the stator high-voltage winding coil ends, a long range of insulationand constructional materials are required.

DISCLOSURE OF THE INVENTION

The present invention is to provide a device for attachment of thegenerator stator high-voltage winding coil ends, the construction ofwhich will permit improving the operating dependability of the generatorand saving insulation and coinstructional materials.

This is attained in a device for attachment of generator statorhigh-voltage winding coil ends herein proposed, comprising insulationspacers disposed on external surfaces of the coil end bars, extraspacers disposed between the coil end bars, and a case made, accordingto the invention, of two coaxial truncated cone members and a part of atorus member made integral therewith and provided with a joint with asealing, said case accommodating the insulation spacers, the extraspacers, spring stops attached inside the case to the side surfacethereof and located opposite each insulation spacer, and platens, witheach platen disposed between two insulation spacers and attached to oneof them, and with the insulation spacers disposed between the windingcoil end bars and spring stops, each surface part of the insulationspacers, platens and spring stops and an inner side surface of the casebeing used for making cooling passages.

An important advantage of the present invention is that electric energycan be saved by virtue of extending periods between overhauls due tohigher dependability of attachment of the stator high-voltage windingcoil ends and due to improved cooling of the winding in the area of thecoil ends thereof. In addition, the foregoing shape of thecoolant-containing case according to the invention contributes tominimizing the dimensions of the generator end area and, hence, toreducing the requirements of structural steel used in manufacture of thecoolant-containing case. The foregoing shape of the case is optimum fromthe point of view of the response thereof to the internal coolantpressure, with the result that the period between overhauls can beprolonged.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in greater detail with reference toa preferred embodiment thereof taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a longitudinal sectional view of a device for attachment ofgenerator stator high-voltage winding coil ends according to theinvention; and

FIG. 2 is a sectional view of same taken along line II--II of FIG. 1according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, the device for attachment of the generator statorhigh-voltage winding coil ends comprises a coolant-containing case 1formed by two coaxial truncated-cone members 2 and 3 coupled to eachother by a part of a torus member 4 made integral therewith andfurnished with a joint 5 incorporating a sealing 6.

The truncated-cone member 2 rests on a generator case tube 7, and thetruncated-cone member 3 rests on a separating cylinder 8 disposedbetween a stator 9 and a rotor 10. In areas of attachment of thetruncated-cone members 2 and 3 to the generator case tube 7 and to theseparating cylinder 8, respective sealings 11 and 12 are installed.Insulation spacers 13 located on external surfaces of the coil ends andmade of such materials as bakelite, and platens 14 attached thereto aresecured to spring stops 15.

The spring stops 15 are attached in their turn to internal surfaces ofthe truncated-cone members 2 and 3 of the case 1, and are arrangedopposite each insulation spacer 13. Each platen 14 is disposed betweenthe two insulation spacers 13. The insulation spacers 13 are disposedbetween bars 16 of the high-voltage winding coil ends and the springstops 15.

The truncated-cone members 2 and 3, the part of the torus member 4, theseparating cylinder 8 and the generator case tube 7 constitute a sealedspace into which a compressed coolant 17 is supplied. The bars 16 of thestator high-voltage winding coil ends 9 are also held by extra spacers18 (FIG. 2) which serve to reinforce the generator stator high-voltagewinding coil ends in a tangential direction.

When the truncated-cone members 2 and 3 are installed, the bars 16 ofthe generator stator high-voltage winding coil ends are fixed on thediameter thereof, on top and bottom by means of the insulation spacers13 and spring stops 15. The platens 14 serve for overlapping the gapsbetween the insulation spacers 13 and for forming cooling passages 19.

The cooling passages 19 are formed by a part of surface of theinsulation spacers 13, spring stops 15 and platens 14, and by theinternal side surface of the case 1.

The coolant 17 (FIG. 1) is supplied under pressure from the sources ofcooling liquid through the cooling passages 19 (FIG. 2) in an axialdirection, and cools the high-voltage winding coil end bars both insideand outside.

The coolant 17 flows through slots in the generator stator 9 to alow-pressure case identical to the case 1 and disposed in the oppositeend of the generator.

Thus, the coolant 17 cools down the generator winding coil ends as wellas active sections of the winding both inside and outside. Thecoolant-containing case 1 shaped in accordance with the presentinvention, and the insulation spacers 13, spring stops 15 and platens 14distributed circumferentially on an end surface of the generatorconstitute a set of the cooling passages 19 (FIG. 2) optimum from thepoint of view of cooling the end area of the generator at minimumturbulence of flowing coolant at an inlet of the stator 9, the passagesbeing distributed evenly on the circumference of the coil ends. As aresult, the cooling efficiency rises, and the intensity of heating ofthe generator end area decreases, particularly in the high-voltagegenerators incorporating the winding coil end bars 16 of great length.Hence, the operating dependability of the generator is improved and thetime between overhauls is prolonged.

The winding coil ends in the stator 9 can be securely attached bothinside and outside owing to the use and appropriate arrangement of thespring stops 15, insulation spacers 13 and platens 14, and due to theproposed shape of the case 1 containing the coolant 19 and comprisingthe truncated-cone members 2 and 3 coupled to each other by the part ofthe torus member 4 incorporating the joint 5, with the case 1 shapedidentically to the coil ends. In the event of the high-voltagegenerators equipped with long coil end bars 16, the foregoing featurealso contributes substantially to the generator operating dependability.In addition, the proposed shape of the case 1 containing the coolant 17(FIG. 1) permits removing the stress concentrating in the areas ofabruptly-curving surfaces, and is optimum from the point of view ofresponse of the case to an internal pressure exerted by the coolant 17on the walls thereof, with the result that the time between overhauls isprolonged and constructional metal requirements of the device areminimized.

The constructional and insulation material requirements are also reducedbecause the device for attachment of the generator stator high-voltagewinding coil ends according to the invention does not include shrinkrings, insulation rings and rubber hoses serving for supply of thecoolant to the stator winding bars.

Assembly of fastening parts in the device for attachment of thegenerator stator high-voltage winding coil ends is greatly simplifiedalong with the procedure of attachment of the coil ends by means of saidparts.

During assembly, the truncated-cone member 3 of the case 1 containingthe coolant 17 is installed in the first place, with the insulationspacers, spring stops 15 and platens 14 already mounted thereupon.

Since all the fastening parts of the device for attachment of thegenerator stator high-voltage coil ends are fastened beforehand to theside walls of the truncated-cone members 2 and 3 and to the winding coilend bars 16 of the generator stator 9, all the assembly procedure isessentially limited to applying and interconnecting the truncated-conemembers 2 and 3, whereby the assembly time required for installation ofthe device for attachment of the generator stator high-voltage windingcoil ends is cut down considerably, and the assembly time of thegenerator as a whole is notably reduced.

Thus, the present invention provides for saving electric energy byvirtue of extending periods between overhauls through improvement independability of attachment of the high-voltage winding coil ends and incooling same. The foregoing shape of the case contributes to a reductionof dimensions of the generator end area and to minimizing of consumptionof structural steel in manufacture of the cooling case.

INDUSTRIAL APPLICABILITY

The invention can most advantageously be used in manufacture ofhigh-power generators, such as turbo-generators operated at thermal andatomic electric power plants.

We claim:
 1. A device for attachment of generator stator high-voltage winding coil ends, comprising insulation spacers disposed on external surfaces of the coil end bars, extra spacers disposed between the coil end bars, characterized in that it also comprises a case (1) made of two coaxial truncated cone members (2 and 3) and a part of a torus member (4) made integral therewith and provided with a joint (5) with a sealing (6), said case (1) accommodating insulation spacers (13), extra spacers (18), spring stops (15) secured inside the case (1) to the side surface thereof and located opposite each insulation spacer (13), and platens (14), each said platen (14) being disposed between two insulation spacers (13) and attached to one of them, the insulation spacers (13) being disposed between the winding coil end bars (16) and spring stops (15), each surface part of the insulation spacers (13), platens (14) and spring stops (15) and an inner side surface of the case (1) being used as cooling passages. 